1. Field of the Invention
The present invention relates to a pump provided with a housing and a rotor that rotates within the housing, the pump drawing fluid into the housing and forcing the drawn fluid to the exterior of the housing. The present invention also relates to an ink jet printer mounting this pump.
2. Description of the Related Art
Rotary pumps are known to the art. One example of a rotary pump is set forth in Principles of New Machinery, 1997, Tenth Edition, p. 203 (27.13 Cary's rotary pump, part 1) “Kikai no so Fukkan Iinkai Hensha, Rikogakusha”. This pump is termed a Cary's rotary pump.
As shown in FIG. 9, a Cary's rotary pump 70 is provided with a housing 73, a rotor 74, a pair of blades (separating members) 76a and 76b and a compressed spring 75. An inlet port 71 and an outlet port 72 are formed in the housing 73. The rotor 74 is cylindrical, and has a groove 78 therein extending across its diameter. The rotor 74 rotates while making contact with a portion of an inner face of the housing 73 between the inlet port 71 and the outlet port 72. The pair of blades (the separating members) 76a and 76b are housed in the groove 78. The compressed spring 75 is housed between the pair of blades (the separating members) 76a and 76b. The compressed spring 75 presses the pair of blades (the separating members) 76a and 76b against the inner face of the housing 73.
When the rotor 74 rotates, the pair of blades 76a and 76b rotates integrally with the rotor 74 while making contact with the inner face of the housing 73. Centrifugal force operating on the pair of blades 76a and 76b increases the force pressing the pair of blades 76a and 76b against the inner face of the housing 73.
The pair of blades 76a and 76b and the rotor 74 separate a cavity within the housing 73 into three divided spaces. That is, the cavity within the housing 73 is separated into: a divided space 77a linked with the inlet port 71, a divided space 77b linked with neither the inlet port 71 nor the outlet port 72, and a divided space 77c linked with the outlet port 72.
When the pair of blades 76a and 76b are rotating integrally with the rotor 74, this rotation occurring in a clockwise direction, and while the pair of blades 76a and 76b are making contact with the inner face of the housing 73, the volume of the divided space 77a linked with the inlet port 71 increases, and the volume of the divided space 77c linked with the outlet port 72 decreases. The increase in volume of the divided space 77a linked with the inlet port 71 draws fluid such as water, air, or the like, into the housing 73 from the inlet port 71. The decrease in volume of the divided space 77c linked with the outlet port 72 elevates the pressure of the fluid drawn into the housing 73, and this pressurized fluid is discharged to the exterior of the housing 73 from the outlet port 72.